1. Field of the Invention
This invention relates to a guidance screen control method of a biometrics authentication device, to a biometrics authentication device, and to a program for same, which utilizes the biometrics characteristics of a portion of the body of a human to perform individual authentication, and in particular relates to a guidance screen control method of a biometrics authentication device, to a biometrics authentication device, and to a program for same, which, at the time of detection of biometrics information, provides guidance for the living body for detection in the range of detection, to perform verification against registered biometrics information.
2. Description of the Related Art
There exist numerous regions of the human body which can be used to differentiate individuals, among them fingerprints and toe-prints, the retina of the eyes, facial features, and blood vessel patterns. Advances in biometrics technology in recent years have been accompanied by proposals of various devices which identify biometrics characteristics which are such regions of the human body to authenticate individuals.
For example, because blood vessels in the palms and fingers and palm-prints provide a comparatively large quantity of individual characteristic data, they are suited to individual authentication where high reliability is required. In particular, the patterns of blood vessels (veins) remain unchanged from the fetus throughout life, and are thought to be completely unique, and so are suited to individual authentication. FIG. 25 through FIG. 28 explain conventional technology for authentication using the palm. As shown in FIG. 25, at the time of registration or authentication, the user brings the palm of a hand 110 close to an image capture device 100. The image capture device 100 emits near-infrared rays, which are incident on the palm of the hand 110. The image capture device 100 receives the near-infrared rays reflected from the palm of the hand 110 using a sensor.
As shown in FIG. 26, hemoglobin within the red corpuscles flowing in the veins 112 has lost oxygen. This hemoglobin (reduced hemoglobin) absorbs near-infrared rays at wavelengths near 760 nanometers. Consequently when near-infrared rays are made incident on the palm of a hand, reflection is reduced only in the areas in which there are veins, and the intensity of the reflected near-infrared rays can be used to identify the positions of veins.
As shown in FIG. 25, a user first registers in a server and card the vein image data for the palm of his own hand, using the image capture device 100. Next, in order to perform individual authentication, the user uses the image capture device 100 of FIG. 25 to cause the vein image data of his own palm to be read.
The individual is authenticated by comparing the patterns of veins in the registered vein image retrieved using the user's ID and in the vein verification image read by the image capture device 100. For example, on comparing the vein patterns in the registered image and a verification image as in FIG. 27, the individual is authenticated as the individual in question. On the other hand, upon comparison of the vein patterns in a registered image and in a verification image as in FIG. 28, the individual is not authenticated (see for example Japanese Patent Laid-open No. 2004-062826).
In such non-contact detection of biometrics information, the living body can move freely relative to the image capture device 100, and in particular the hand can move freely. On the other hand, the portion 100 for detection of the body must be positioned within the image capture range of the image capture device 100 to enable accurate detection. Methods to achieve this have been proposed in which, each time an image is captured, the position and orientation of the hand is detected, and when accurate image capture is not possible, a display or voice output is employed to convey the inappropriateness of the position or orientation of the hand (see for example WO 04/021884). By means of this method, because detection is contact-free, accurate detection of biometrics information is possible even when there is no sense of resistance to the hand or body during detection.
In this detection of biometrics information, the body, and in particular the hand moves freely. In order to perform rapid biometrics authentication, however, it is necessary to perform image capture frequently, detect appropriate images, and output these to the authentication process. Hence even if, as a consequence of the image capture state at each image capture, a display is presented indicating that the body part position or orientation is inappropriate, there is the possibility that the display may change in a short period of time, causing the user to be confused.
Similarly, because the display switches instantaneously, the screen may appear to the user to be flickering, so that again the display is not used effectively to guide the user.